I've always thought groups like Rolling Thunder, who I really admire, would be enhanced by having the odd black face in the ranks. But I think the whole idea of re-enacting and the military thing is predominantly a, how do I say this nicely, indigenous thing when it comes to the UK. Can't speak for anywhere else. I don't remember ever seeing a black re-enactor or vehicle owner. The counter side to this is when a bureaucrat notices this fact and does the hobby a damage for lack of diversity. Maybe, and just maybe, this is why similar notions - however mischievious, make it in to AGM agendas.
I don't think this is a subject that can go anywhere as a long term discussion. We are who we are and we like what we like. While I would never claim to be politically correct and a paid up member of the Brotherhood of Man, I would never discriminate against people who wanted to adance the MV/military history scene. Nor do I think would anyone else. The more the merrier. The black gay lesbian vegan skateboarders can still put their cottage cheese in the clubhouse fridge - if they nick my KitKats they will get the same response as anyone else. HMVF polo shirts come to fit body size not content.